1. Field of the Invention
The present invention pertains to a pressure regulator valve having a control piston and closure member adapted to minimize the variation between the valve opening pressure and the continuous operating pressure. The valve is particularly adapted for use in conjunction with high pressure liquid jet blasting or cutting apparatus.
2. Background
In the development of high pressure hydraulic apparatus, such as water jet cutting and blast cleaning apparatus and hydrostatic test equipment, operating pressures have now commonly reached values in the range of 10,000 to 50,000 psig. The development of working liquid handling equipment operating in these pressure ranges presents special problems. In certain applications of water jet blast cleaning or cutting equipment, for example, it is desirable to regulate the pump discharge pressure to a substantially constant value regardless of the rate of usage of the pump flow. For example, it may be desired to have several on-off type nozzles or jetting guns connected to a single or common pump discharge line. In such an application it is desirable to provide a pressure regulating valve which will regulate the pump discharge pressure to a substantially constant value so that one or more guns may be properly operated from the same fluid source.
The high operating pressures of liquid jet blast cleaning or cutting equipment requires that the operating components be mechanically strong enough to withstand the operating pressures but also be mechanically simple and adapted for easy replacement of those component parts which are subject to high rates of wear due to the pressure and flow characteristics of the liquid at such operating conditions. Because of the high operating pressures a component such as a pressure regulating valve is particularly difficult to design because of the extremely high actuating forces that must be applied to bias the valve closure member in the closed or controlled position. At the same time the valve must be adapted to operate satisfactorily over a long period of time, be mechanically simple and cost effective and also be particularly adapted for replacement of component parts. These requisites have presented several problems to the art worker.
Prior to the development of the present invention, for example, it has been common to utilize water jet cutting equipment wherein a simple on-off or so-called dump valve is used in conjunction with the jet cleaning guns as in means of flow control. However, the development of a pressure regulating valve as described and claimed herein has been particularly beneficial for such applications and those skilled in the art will recognize that many other applications for the improved valve of the present invention will be appropriate and desirable.